Lime (fruit)

Limes are the fruit of several citrus species, most of which are hybrids within the genus *Citrus* (family Rutaceae). They are typically small, round or oval, with green skin and flesh, and a sharp, sour taste that comes from high levels of citric acid. These fruits are grown widely in tropical and subtropical areas and are used in cooking, medicine, and decoration. The name "lime" covers many different citrus fruits, such as Key lime, Persian lime, Kaffir lime, finger lime, blood lime, and desert lime.

Most limes are 3–6 cm (1–2.5 inches) across, with a thin to medium-thick rind that is green when unripe and can turn yellow when fully ripe. The pulp is juicy and very acidic. Commercially, limes are usually picked while still green, when their flavor and acidity are strongest. The trees are small, evergreen shrubs or low trees with shiny leaves and fragrant white flowers. Seediness varies: Key limes tend to have many seeds, while Persian limes are almost seedless.

Limes do not belong to a single botanical group. Most commercial types are hybrids of citron (*C. medica*), mandarin (*C. reticulata*), pomelo (*C. maxima*), and sometimes micrantha. Key lime (*Citrus × aurantiifolia*) is small and seedy, originally from Southeast Asia. Persian lime (*Citrus × latifolia*) is larger, nearly seedless, and a hybrid of Key lime and lemon (*C. × limon*); it is the most widely produced lime. Kaffir lime (*C. hystrix*) has a bumpy, aromatic rind and is common in Southeast Asian cooking; it is also called Makrut lime. Australian desert lime (*C. glauca*) and finger lime (*C. australasica*) are native to Australia and used in niche dishes. Other hybrids include blood lime, Rangpur lime, Spanish lime (*Melicoccus bijugatus*—not a true citrus), and sweet lime (*Citrus limetta*). Non-citrus plants called limes include *Zanthoxylum fagara* and *Adelia ricinella*. In Britain, "lime tree" can also refer to *Tilia* species, which are unrelated to citrus.

Limes originated in tropical Southeast Asia, especially Indonesia and South China, and spread through human travel and trade. Kaffir lime was one of the first citrus fruits brought beyond its native range. Limes reached Micronesia and Polynesia during the Austronesian expansion (around 3000–1500 BCE), and later arrived in the Middle East and Mediterranean via the spice trade by at least 1200 BCE. In the 1800s, British sailors ate citrus, including limes, to prevent scurvy, which led to the nickname "limey." This practice was kept as a military secret.

In 2023, global production of limes (combined with lemons) reached 23.6 million tonnes, with India and Mexico as the top producers.

Limes are prized for the acidity of their juice and the aroma of their zest. Lime juice is used in limeade, cocktails (such as margarita, gimlet, and daiquiri), ceviche, and guacamole. Dried limes (limoo or black lime) appear in Persian, Iraqi, and Eastern Arabian spice blends. Key lime is the signature flavor of Key lime pie. Desert lime is used in Australian marmalade. Non-culinary uses include perfume, cleaning products, and aromatherapy, which rely on lime extracts and essential oils.

Raw limes are about 88% water, 10% carbohydrates, and less than 1% fat and protein. Per 100 grams, they provide 35% of the Daily Value of vitamin C. Lime juice contains roughly 47 grams of citric acid per liter—about twice as much as grapefruit juice and five times as much as orange juice. The pulp and peel also contain various phytochemicals, including polyphenols and terpenes.

Contact with lime peel or juice, followed by exposure to ultraviolet light, can cause phytophotodermatitis (sometimes called "margarita photodermatitis"). This reaction is due to phototoxic compounds called furanocoumarins, such as bergapten, limettin, psoralen, and xanthotoxin. The peel has higher concentrations of these compounds than the pulp, making it more phototoxic.